The invention relates to a dioptric sight including an adjustable iris diaphragm and a plurality of color and/or polarization filters.
Such dioptric sights are described, for example, in U.S. Pat. Nos. 4,856,879 and 4,392,723.
In the arrangements described in these patents as well as in other known arrangements, the color filter discs and polarizing discs have a diameter of only about 4 mm corresponding to the sight channel of the eyepiece. The small size of the filter discs; however, permits only insufficient cleaning of the discs since, with the usual cleaning procedures, a circumferential rim of dirt remains at the outer edge of the disc which may obstruct the view. This is also true for the arrangement according to U.S. Pat. No. 4,856,879 in which disassembly and removal of the discs for cleaning is easily possible. Practice also shows that, because of their small size, the cleaned filter discs are easily contaminated which may happen just by grasping the discs. The small discs permit a highly compact sight design which however in practice encounters some problems particularly with regard to the servicing of the filter discs.
It is further pointed out in the above-cited patent that dioptric sights of the type described are needed in relatively large numbers and that, therefore, they should be designed such that they can be manufactured in an economical manner. Although the dioptric sight described in that patent can in fact be economically manufactured, practice has shown that the design is still too expensive for most hunters; they would generally prefer a more simple, less expensive sight.
It is the principal object of the present invention to provide a dioptric sight design with filter discs which can be easily removed and reinstalled so that they can be properly cleaned and with design features which permit easy and inexpensive manufacture.